Instruction Manual
D200160X012
4195K Controllers
July 2018
40
Auto/Manual Station (suffix letter E) Operation
A controller with the auto/manual station (designated by the suffix letter E in the type number) has piping on the
output side of the relay as shown in figure 4‐8. Supply pressure to the relay is also applied to the manual loader. The
manual loader, functioning as a regulator, applies pressure to one side of the plastic tube and to the auto/manual
switch. Output pressure from the relay registers on the other side of the plastic tube as well as in the auto/manual
switch.
Figure 4‐8. Fisher 4195KB and KC Auto/Manual Station Schematic
AUTOMATIC
POSITION
OUTPUT PRESSURE
TO FINAL CONTROL
ELEMENT
SUPPLY PRESSURE
RELAY
AUTO/MANUAL
SWITCH
MANUAL LOADER
MANUAL
LOADER
KNOB
MANUAL
POSITION
AUTO/MANUAL
SWITCH
OUTPUT PRESSURE
TO FINAL CONTROL
ELEMENT
PLASTIC TUBE
METAL BALL
RELAY OUTPUT PRESSURE
SUPPLY PRESSURE
MANUAL LOADER OUTPUT PRESSURE
48A5230‐A
A2999‐1
When the auto/manual switch is in the MANUAL position, the manual loader output is channeled through the
auto/manual switch and becomes the controller output. When the auto/manual switch is in the AUTO position, the
relay output is channeled through the switch to become the controller output.
Before the auto/manual switch is operated, the relay output must equal the manual loader output to avoid bumping
the process. Adjusting the set point varies the pressure on the left‐hand side of the plastic tube. Adjusting the manual
loader knob varies the pressure on the right‐hand side. When the pressures are equal, the metal ball is centered in the
tube and it is held in place by a small magnet. A pressure imbalance forces the ball to one end of the tube where it
forms a seal, blocking air flow through the tube.